Coating on a plastic substrate and a coated plastic product

ABSTRACT

The invention relates in general level to a method for coating plastic products including large surface areas. The invention also relates to coated plastic products manufactured by the method. The coating is carried out by employing ultra short pulsed laser deposition wherein pulsed laser beam is scanned with a rotating optical scanner including at least one mirror for reflecting the laser beam. The invention has several both industrially and qualitatively advantageous effects such as low production temperatures accomplishing the coating of plastic products, high coating production rate, excellent coating properties and overall low manufacturing costs.

FIELD OF INVENTION

The invention relates generally to a method for coating plastic productscomprising large surface areas by ultra short pulsed laser ablation. Theinvention also relates to products manufactured by the method. Theinvention has many advantageous effects such as low coating temperaturesaccomplishing coating of heat-sensitive plastic products, high coatingproduction rate, excellent coating properties and low manufacturingcosts.

BACKGROUND Plastic Products

Plastic covers a range of synthetic or semisynthetic polymerizationproducts. They are composed of organic condensation or addition polymersand may contain other substances to improve performance or economics.There are few natural polymers generally considered to be “plastics”.Plastics can be formed into objects of films and even fibers. Their nameis derived from the fact that they are malleable, having property ofplasticity. In other words, they are very versatile in processingoffering a very broad scope of product design. That is one of the mainreasons why the plastics have gained so much use after their invention.The plastic products are lightweight, and often they possess goodbreak-resistance and non-splittering features. Additionally, severalplastic grades such as polycarbonates can be prepared to be transparent.

Plastics can be classified in many ways, but most commonly by theirpolymer backbone (polyvinyl chloride polyethylene, polyethylmethacrylate, and other acrylics, silicones, polyurethanes etc. Otherclassifications include thermoplastic thermoset, elastomer, engineeringplastics, addition or condensation or polyaddition, and glass transitionof temperature. Some plastics are partially crystalline and partiallyamorphous in molecular structure, giving the both a melting point (thetemperature at which the attractive intermolecular forces are overcome)and one or more glass transitions (temperatures above which the extentof localized molecular is substantially increased). So-calledsemi-crystalline plastics include polyethylene, polypropylene,poly(vinyl chloride), polyamides (nylons), polyesters and somepolyurethanes. Many plastics are completely amorphous, such aspolystyrene and its copolymers, poly(methyl methacrylate), and all thethermosets.

Some of the problems associated with plastics are their heatsensitivity, their poor wear and mechanical properties and easydecomposition due to chemical and radiation-based interactions (such asnatural UV-radiation) Rey-muuta???

Such problems have been tackled by introducing some special plasticssuch as PEEK (Polyetheretherketones). PEEK possesses extraordinarymechanical properties, the Young's modulus being 3.6 GPA and tensilestrength of 170 Mpa, melts at around 350° C. and is “highly resistant tothermal degradation”.

The second approach to tackle these problems is to introduce differentcoatings on plastics. Most of the CVD- and PVD-based methods requireelevated process temperatures being thus not employable to coatplastics. Hence if coated, most of the plastics are coated withdifferent lacquers being generally not able to give properties requiredfrom present products.

Laser-Ablation

In the recent years, considerable development of the laser technologyhas provided means to produce very high-efficiency laser systems thatare based on semi-conductor fibres, thus supporting advance in so calledcold ablation methods.

At the priority date of the current application, solely fibrousdiode-pumped semiconductor laser is competing with light-bulb pumpedone, which both have the feature according to which the laser beam islead first into a fibre, and then forwarded to the working target. Thesefibrous laser systems are the only ones to be applied in to the laserablation applications in an industrial scale.

The recent fibres of the fibre lasers, as well as the consequent lowradiation power seem to limit the materials to be used in thevaporization/ablation as the vaporization/ablation targets.Vaporizing/ablating aluminium can be facilitated by a small-pulsedpower, whereas the more difficult substances to be vaporized/ablated asCopper, Tungsten, etc. need more pulsed power. The same applies intosituation in which new compounds were in the interest to be brought upwith the same conventional techniques. Examples to be mentioned are forinstance manufacturing diamond directly from carbon (graphite) oralumina production straight from aluminium and oxygen via theappropriate reaction in the vapour-phase in post-laser-ablationconditions.

On one hand, one of the most significant obstacles to the forwardingprogress of fibre-laser technology seems to be the fibre capability ofthe fibre to tolerate the high power laser pulses without break-up ofthe fibre or without diminished quality of the laser beam.

When employing novel cold-ablation, both qualitative and production raterelated problems associated with coating, thin film production as wellas cutting/grooving/carving etc. has been approached by focusing onincreasing laser power and reducing the spot size of the laser beam onthe target. However, most of the power increase was consumed to noise.The qualitative and production rate related problems were stillremaining although some laser manufacturers resolved the laser powerrelated problem. Representative samples for both coating/thin film aswell as cutting/grooving/carving etc. could be produced only with lowrepetition rates, narrow scanning widths and with long working timebeyond industrial feasibility as such, highlighted especially for largebodies.

If the energy content of a pulse is kept constant, the power of thepulse increases in the decrease of the pulse duration, the problem withsignificance increases with the decreasing laser-pulse duration. Theproblems are significant even with the nano-second-pulse lasers,although they are not applied as such in cold ablation methods.

The pulse duration decrease further to femto or even to atto-secondscale makes the problem almost irresolvable. For example, in apico-second laser system with a pulse duration of 10-15 ps the pulseenergy should be 5 μJ for a 10-30 μm spot, when the total power of thelaser is 100 W and the repetition rate 20 MHz. Such a fibre to toleratesuch a pulse is not available at the priority date of the currentapplication according to the knowledge of the writer at the very date.

The production rate is directly proportional to the repetition rate orrepetition frequency. On one hand the known mirror-film scanners(galvano-scanners or back and worth wobbling type of scanners), which dotheir duty cycle in way characterized by their back and forth movement,the stopping of the mirror at the both ends of the duty cycle issomewhat problematic as well as the accelerating and deceleratingrelated to the turning point and the related momentary stop, which alllimit the utilizability of the mirror as scanner, but especially also tothe scanning width. If the production rate were tried to be scaled up,by increasing the repetition rate, the acceleration and decelerationcause either a narrow scanning range, or uneven distribution of theradiation and thus the plasma at the target when radiation hit thetarget via accelerating and/or decelerating mirror.

If trying to increase the coating/thin film production rate by simplyincreasing the pulse repetition rate, the present above mentioned knownscanners direct the pulses to overlapping spot of the target areaalready at the low pulse repetition rates in kHz-range, in anuncontrolled way. At worst, such an approach results in release ofparticles from the target material, instead of plasma but at least inparticle formation into plasma. Once several successive laser pulses aredirected into the same location of target surface, the cumulative effectseems to erode the target material unevenly and can lead to heating ofthe target material, the advantages of cold ablation being thus lost.

The same problems apply to nano-second range lasers, the problem beingnaturally even more severe because of the long lasting pulse with highenergy. Here, the target material heating occurs always, the targetmaterial temperature being elevated to approximately 5000 K. Thus, evenone single nano-second range pulse erodes the target materialdrastically, with aforesaid problems.

In the known techniques, the target may not only ware out unevenly butmay also fragment easily and degrade the plasma quality. Thus, thesurface to be coated with such plasma also suffers the detrimentaleffects of the plasma. The surface may comprise fragments, plasma may benot evenly distributed to form such a coating etc. which are problematicin accuracy demanding application, but may be not problematic, withpaint or pigment for instance, provided that the defects keep below thedetection limit of the very application.

The present methods ware out the target in a single use so that sametarget is not available for a further use from the same surface again.The problem has been tackled by utilising only a virgin surface of thetarget, by moving target material and/or the beam spot accordingly.

In machining or work-related applications the left-overs or the debriscomprising some fragments also can make the cut-line uneven and thusinappropriate, as the case could for instance in flow-control drillings.Also the surface could be formed to have a random bumpy appearancecaused by the released fragments, which may be not appropriate incertain semiconductor manufacturing, for instance.

In addition, the mirror-film scanners moving back and forth generateinertial forces that load the structure itself, but also to the bearingsto which the mirror is attached and/or which cause the mirror movement.Such inertia little by little may loosen the attachment of the mirror,especially if such mirror were working nearly at the extreme range ofthe possible operational settings, and may lead to roaming of thesettings in long time scale, which may be seen from uneven repeatabilityof the product quality. Because of the stoppings, as well as thedirection and the related velocity changes of the movement, such amirror-film scanner has a very limited scanning width so to be used forablation and plasma production. The effective duty cycle is relativelyshort compared to the whole cycle, although the operation is anywayquite slow. In the point of view of increasing the productivity of asystem utilising mirror-film scanners, the plasma production rate is inprerequisite slow, scanning width narrow, operation unstable for longtime period scales, but yield also a very high probability to getinvolved with unwanted particle emission in to the plasma, andconsequently to the products that are involved with the plasma via themachinery and/or coating.

SUMMARY OF THE INVENTION

The maintenance cost for plastic products is huge and steadilyincreasing and there is a great need for coating technologies forespecially plastic products comprising large surface areas. The productlifetime should be increased and the maintenance costs should belowered, sustainable development being a prerequisite. The coating andespecially uniform coating of large plastic surfaces with one or severalof the following properties: excellent optical properties, chemicaland/or wear resistance, thermal resistance, resistivity, coatingadhesion, self-cleaning properties and possibly, tribological propertieshas remained an unsolved problem. Partly, this is because of heatsensitive nature of plastic product itself partly because the overalllack of methods to solve previously mentioned coating problems,regardless the substrate to be coated.

There is also an increasing demand for various bendable electronics.Plastics possess several excellent properties to be employed as ascaffold for such devices, but the techniques to manufacture suchcomplex devices on plastics, especially on industrial scale remainnon-existing.

Neither recent high-technological coating methods, nor present coatingtechniques related to laser ablation either in nanosecond or coldablation range (pico-, femto-second lasers) can provide any feasiblemethod for industrial scale coating of plastic products, especiallycomprising larger surfaces. The present CVD- and PVD-coatingtechnologies require high-vacuum conditions making the coating processbatch wise, thus non-feasible for industrial scale coating of most ofthe present metal products. Moreover, the distance between the plasticmaterial to be coated and the coating material to be ablated is long,typically over 50 cm, making the coating chambers large and vacuumpumping periods time- and energy-consuming. Such high-volume vacuumedchambers are also easily contaminated with coating materials in thecoating process itself, requiring continuous and time-consuming cleaningprocesses.

While trying to increase the coating production rate in presentlaser-assisted coating methods, various defects such as pinholes,increased surface roughness, decreased or disappearing opticalproperties, particulates on coating surface, particulates in surfacestructure affecting corrosion pathways, decreased surface uniformity,decreased adhesion, inadequate resistivity (electrical), unsatisfactorysurface thickness and tribological properties etc. take place.

The present coating methods also drastically restrict the materialsemployable for coating purposes in general and thus, limit the scope ofdifferent coated metal products available on market today. Ifapplicable, the target material surface is eroded in a manner that onlythe outmost layer of the target material can be employed for coatingpurposes. The rest of the material is either wasted or must be subjectedto reprocessing before reuse. An aim of the current invention is tosolve or at least to mitigate the problems of the known techniques.

A first object of this invention is to provide a new method how to solvea problem to coat a certain surface of a plastic product by pulsed laserdeposition that so that the uniform surface area to be coated comprisesat least 0.2 dm². A second object of this invention is to provide newplastic products being coated by pulsed laser deposition so that thecoated uniform surface area comprises at least 0.2 dm². A third objectof this invention is to provide at least a new method and/or relatedmeans to solve a problem how to provide available such fine plasmapractically from any target to be used in coating of plastic products,so that the target material do not form into the plasma any particulatefragments either at all, i.e. the plasma is pure plasma, or thefragments, if exist, are rare and at least smaller in size than theablation depth to which the plasma is generated by ablation from saidtarget.

A fourth object of the invention is to provide at least a new methodand/or related means to solve how to coat the uniform surface area of aplastic product with the high quality plasma without particulatefragments larger in size than the ablation depth to which the plasma isgenerated by ablation from said target, i.e. to coat substrates withpure plasma originating to practically any material.

A fifth object of this invention is to is to provide a good adhesion ofthe coating to the uniform surface area of a plastic product by saidpure plasma, so that wasting the kinetic energy to particulate fragmentsis suppressed by limiting the existence of the particulate fragments ortheir size smaller than said ablation depth. Simultaneously, theparticulate fragments because of their lacking existence in significantmanner, they do not form cool surfaces that could influence on thehomogeneity of the plasma plume via nucleation and condensation relatedphenomena.

A sixth object of the invention is to provide at least a new methodand/or related means to solve a problem how to provide a broad scanningwidth simultaneously with fine plasma quality and broad coating widtheven for large plastic bodies in industrial manner.

A seventh object of the invention is to provide at least a new methodand/or related means to solve a problem how to provide a high repetitionrate to be used to provide industrial scale applications in accordancewith the objects of the invention mentioned above.

An eighth object of the invention is to provide at least a new methodand/or related means to solve a problem how to provide fine plasma forcoating of uniform plastic surfaces to manufacture products according tothe first to seven objects, but still save target material to be used inthe coating phases producing same quality coatings/thin films whereneeded.

A further object of the invention is to use such method and meansaccording previous objects to solve a problem how to cold-work and/orcoat surfaces for coated products.

The present invention is based on the surprising discovery that plasticproducts Comprising large surfaces can be coated with industrialproduction rates and excellent qualities regarding one or more oftechnical features such as optical transparency, chemical and/or wearresistance, scratch-free properties, thermal resistance and/orconductivity, coating adhesion, self-cleaning properties and possibly,tribological properties, particulate-free coatings, pinhole-freecoatings and electronic conductivity by employing ultra short pulsedlaser deposition in a manner wherein pulsed laser beam is scanned with arotating optical scanner comprising at least one mirror for reflectingsaid laser beam. Normally, plastic products are especially difficult tocoat due to their extreme heat-sensitivity.

Moreover, the present method accomplishes the economical use of targetmaterials, because they are ablated in a manner accomplishing the reuseof already subjected material with retained high coating results. Thepresent invention further accomplishes the coating of plastic productsin low vacuum conditions with simultaneously high coating properties.Moreover, the required coating chamber volumes are dramatically smallerthan in competing methods. Such features decrease dramatically theoverall equipment cost and increase the coating production rate. In manypreferable cases, the coating equipment can be fitted intoproduction-line in online manner.

The coating deposition rates with 20 W USPLD-apparatus are 2 mm³/min.While increasing the laser power to 80 W, the USPLD coating depositionrate is increased to 8 mm³/min, accordingly. According to the invention,the increase in deposition rate can now be fully employed to highquality coating production.

In this patent application the term “coating” means forming material ofany thickness on a substrate. Coating can thus also mean producing thinfilms with thickness of e.g. <1 μm.

Various embodiments of the inventions are combinable in suitable part.

When read and understood the invention, the skilled men in the art mayknow many ways to modify the shown embodiments of the invention,however, without leaving the scope of the invention, which is notlimited only to the shown embodiments which are shown as examples of theembodiments of the invention.

FIGURES

The described and other advantages of the invention will become apparentfrom the following detailed description and by referring to the drawingswhere:

FIG. 1 illustrates an exemplary galvano-scanner set-up comprising twogalvano-scanners employed in state of the art cold ablationcoating/thin-film production and in machining and other work-relatedapplications. The number of galvano-scanners directing the laser beamvaries but is typically limited to one single galvano-scanner,

FIG. 2 illustrates ITO-coating on polycarbonate sheet (˜100 mm×30 mm)produced by employing a prior art vibrating mirror (galvo-scanner), indifferent ITO thin-film thicknesses (30 nm, 60 nm and 90 nm).

FIG. 3 illustrates the situation wherein prior art galvanometric scanneris employed in scanning laser beam resulting in heavy overlapping ofpulses with repetition rate of 2 Mhz.

FIG. 4 illustrates one polycarbonate sheet coated comprisingwear-resistant coating according to the invention

FIG. 5 illustrates one possible turbine scanner mirror employed inmethod according to the invention,

FIG. 6 illustrates the movement of the ablating beam achieved by eachmirror in the example of FIG. 5,

FIG. 7 illustrates beam guidance through one possible rotating scannerto be employed according to the invention,

FIG. 8 illustrates beam guidance through one possible rotating scannerto be employed according to the invention,

FIG. 9 illustrates beam guidance through one possible rotating scannerto be employed according to the invention,

FIG. 10 illustrates one embodiment of coated product according to theinvention,

FIG. 11 illustrates one embodiment of coated product according to theinvention,

FIG. 12 illustrates one embodiment of coated product according to theinvention,

FIG. 13 illustrates one embodiment of coated product according to theinvention,

FIG. 14 a illustrates one embodiment of coated product according to theinvention, having a plurality of different layers forming mirrorstructure, one layer being always comprised of plastic,

FIG. 14 b illustrates one embodiment of coated product according to theinvention, having a plurality of different layers forming mirrorstructure, one layer being always comprised of plastic,

FIG. 14 c illustrates one embodiment of coated product according to theinvention, having a plurality of different layers forming mirrorstructure, one layer being always comprised of plastic,

FIG. 15 illustrates one embodiment of multi-coated product according tothe invention,

FIG. 16 illustrates one embodiment of multi-coated product according tothe invention,

FIG. 17 illustrates two embodiments of coated product according to theinvention,

FIG. 18 illustrates one embodiment of multi-coated product according tothe invention,

FIG. 19 illustrates two embodiments of multi-coated product according tothe invention,

FIG. 20 illustrates one embodiment of coated product according to theinvention,

FIG. 21 illustrates two embodiments of coated product according to theinvention,

FIG. 22 illustrates one embodiment of multi-coated product according tothe invention,

FIG. 23 illustrates one embodiment of coated product according to theinvention and one state of the art product,

FIG. 24 illustrates optical micrograph of wear track on commercialcoated plycarbonate plate,

FIG. 25 illustrates comparable optical micrograph of wear track oncoated plycarbonate plate according to the invention, with identicalwear track to that of FIG. 24,

FIG. 26 illustrates the surface profile of the wear track of commercialPC-plate after wear testing,

FIG. 27 illustrates the surface profile of the wear track of YAG-coatingaccording to the invention,

FIG. 28 a illustrates an embodiment according to the invention, whereintarget material ablated by scanning the laser beam with rotating scanner(turbine scanner).

FIG. 28 b illustrates an exemplary part of target material of FIG. 28 a.

FIG. 28 c illustrates an exemplary ablated area of target material ofFIG. 28 b.

FIG. 29 a illustrates an exemplary way according to the invention toscan and ablate target material with turbine scanner (rotating scanner).

FIG. 30 a illustrates plasma-related problems of known techniques.

FIG. 30 b illustrates plasma-related problems of known techniques.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

According to the invention there is provided a method for coating acertain surface of a plastic product by laser ablation in which methodthe uniform surface area to be coated comprises at least 0.2 dm² and thecoating is carried by employing ultra short pulsed laser depositionwherein pulsed laser beam is scanned with a rotating optical scannercomprising at least one mirror for reflecting said laser beam.

With plastic products is hereby meant but not limited to metal productssuch as for construction as whole, interior and decorative use, forcertain limitations to machinery, vehicles such as cars, trucks,motorcycles and tractors, airplanes, ships, boats, trains, rails, tools,medical products, housings of electronic devices, power plugs, car rearand front lamps, canteen trays, thermos flasks, tea strainers, hairdryerand binocular housings, milking cans, film cassettes, switch relays,fishing rod reels, traffic-light housings and lenses, lenses of mobiledevices and cameras, lightning, profiles, frames, component parts,process equipment, pipes and tanks for various industries such aschemical industries, power and energy industries, space ships, plainmetal sheets, military solutions, ventilation, bearings, piston parts,pumps, compressor plate valves, cable insulation applications, inapplications comprising ultra-high vacuum conditions, screws, waterpipes, drills and their parts etc. The plastic product must not benecessarily of plastic as such. According to the invention, all theproducts comprising plastic surfaces regardless whether their metalcontent is 100% or 0.1% can be coated with now presented method. Some ofthe possible embodiments of the invention are illustrated in FIGS. 4 and10-22.

Ultra Short Laser Pulsed Deposition is often shortened USPLD. Saiddeposition is also called cold ablation, in which one of thecharacteristic features is that opposite for example to competingnanosecond lasers practically no heat transfer takes place from theexposed target area to the surroundings of this area, the laser pulseenergies being still enough to exceed ablation threshold of targetmaterial. The pulse lengths are typically under 50 ps, such as 5-30 ps.i.e. ultra short, the cold ablation being reached with pico-second,femto-second and atto-second pulsed lasers. The material evaporated fromthe target by laser ablation is deposited onto a substrate that is heldnear room temperature. Still, the plasma temperature reaches 1.000.000 Kon exposed target area. The plasma speed is superior, gaining even100.000 m/s and thus, better prospective for adequate adhesion ofcoating/thin-film produced.

In another preferred embodiment of the invention, said uniform surfacearea comprises at least 0.5 dm². In a still preferred embodiment of theinvention, said uniform surface area comprises at least 1.0 dm². Theinvention accomplishes easily also the coating of products comprisinguniform coated surface areas larger than 0.5 m², such as 1 m² and over.As the process is especially beneficial for coating large surfaces withhigh quality plasma, it meets an underserved or unserved market ofseveral different plastic products.

In industrial applications, it is important to achieve high efficiencyof laser treatment. In cold ablation, the intensity of laser pulses mustexceed a predetermined threshold value in order to facilitate the coldablation phenomenon. This threshold value depends on the targetmaterial. In order to achieve high treatment efficiency and thus,industrial productivity, the repetition rate of the pulses should behigh, such as 1 MHz, preferably over 2 MHz and more preferably over 5MHz. As mentioned earlier, it is advantageous not to direct severalpulses into same location of the target surface because this causes acumulating effect in the target material, with particle depositionleading to bad quality plasma and thus, bad quality coatings andthin-films, undesirable eroding of the target material, possible targetmaterial heating etc. Therefore, to achieve a high efficiency oftreatment, it is also necessary to have a high scanning speed of thelaser beam. According to the invention, the velocity of the beam at thesurface of the target should generally be more than 10 m/s to achieveefficient processing, and preferably more than 50 m/s and morepreferably more than 100 m/s, even such speeds as 2000 m/s. However, inthe optical scanners based on vibrating mirror the moment of inertiaprevents achieving sufficiently high angular velocity of the mirror. Theobtained laser beam at the target surface is therefore just a few m/s,FIG. 1 illustrating an example of such vibrating mirror, also calledgalvano-scanner.

As the present coating methods employing galvano-scanners can producescanning widths at most 10 cm, preferably less, the present inventionalso accomplishes much more broader scanning widths such as 30 cm andeven over 1 meter with simultaneously excellent coating properties andproduction rates.

According to one embodiment of the invention, rotating optical scanneris here meant scanners comprising at least one mirror for reflectinglaser beam. Such a scanner and its applications are described in patentapplication FI20065867. According to another embodiment of theinvention, rotating optical scanner comprises at least three mirrors forreflecting laser beam. In one embodiment of the invention, in thecoating method employs a polygonal prism illustrated in FIG. 5. Here, apolygonal prism has faces 21, 22, 23, 24, 25, 26, 27 and 28. Arrow 20indicates that the prism can be rotated around its axis 19, which is thesymmetry axis of the prism. When the faces of the prism of the FIG. 5are mirror faces, advantageously oblique in order to achieve scanningline, arranged such that each face in its turn will change, by means ofreflection, the direction of radiation incident on the mirror surface asthe prism is rotated around its axis, the prism is applicable in themethod according to an embodiment of the invention, in its radiationtransmission line, as part of a rotating scanner, i.e. turbine scanner.FIG. 5 shows 8 faces, but there may be considerably more faces thanthat, even dozens or hundreds of them. FIG. 5 also shows that themirrors are at the same oblique angle to the axis, but especially in anembodiment including several mirrors, the said angle may vary in stepsso that, by means of stepping within a certain range, a certain steppedshift on the work spot is achieved on the target, illustrated in FIG. 6,among other things. The different embodiments of invention are not to belimited into various turbine scanner mirror arrangements regarding forexample the size, shape and number of laser beam reflecting mirrors.

The structure of the turbine scanner, FIG. 5, includes at least 2mirrors, preferably more than 6 mirrors, e.g. 8 mirrors (21 to 28)positioned symmetrically around the central axis 19. As the prism 21 inthe turbine scanner rotates 20 around the central axis 19, the mirrorsdirect the radiation, a laser beam, for instance, reflected from spot29, accurately onto the line-shaped area, always starting from one andthe same direction (FIG. 6). The mirror structure of the turbine scannermay be non-tilted (FIG. 7) or tilted at a desired angle, e.g. FIGS. 8and 9. The size and proportions of the turbine scanner can be freelychosen. In one advantageous embodiment of the coating method it has aperimeter of 30 cm, diameter of 12 cm, and a height of 5 cm.

In an embodiment of the invention it is advantageous that the mirrors 21to 28 of the turbine scanner are preferably positioned at oblique anglesto the central axis 19, because then the laser beam is easily conductedinto the scanner system.

In a turbine scanner according to be employed according to an embodimentof the invention (FIG. 5) the mirrors 21 to 28 can deviate from eachother in such a manner that during one round of rotational movementthere are scanned as many line-shaped areas (FIG. 6) 29 as there aremirrors 21 to 28.

According to the invention, the surface to be coated can comprise wholeor a part of the plastic product surface.

In one especially preferred embodiment of invention, thin plastic sheetsfor various use as in construction or interior finishing, the wholesheet is coated in order to gain the preferred effect or effects ofcoating. One such representative product according to inventioncomprising a copper thin sheet of 1200 mm×1500 mm with thickness of 1 mmand coated first with CuO₂ and finished with a protective coating oftransparent ATO (aluminumtitanoxide) is illustrated in FIG. 4. CuO₂gives the interior effect, ATO giving wear resistance as well aspreventing the leakage of harmful copper compound into nature. ATO canbe replaced with for example aluminum oxide, ytrium stabilized zirconiumoxide, yttrium aluminum oxide, titanium dioxide and various carbon basedcoatings.

In one preferred embodiment of the invention laser ablation is carriedout under vacuum of 10⁻¹ to 10⁻¹² atmospheres. High vacuum conditionsrequire quite long pumping times, and thus prolonged production times ofcoatings. With certain high end-products this is not so big problem, butwith for example commodity products especially comprising largersurfaces this definitely is. If taking into account to for example novelwear- and scratch-free coatings, chemically inert coatings, resistivecoatings, tribological coatings, thermally resistant and/or thermallyconductive coatings, electrically conductive coatings and possiblysimultaneously excellent transparencies, there simply aren't any coatingmethods available for said products, neither from technological point ofview and/or from economical point of view.

Thus, in a specially preferred embodiment of invention, the laserablation is carried out under vacuum of 10⁻¹ to 10⁻⁴ atmospheres.According to the invention, excellent coating/thin-film properties canbe achieved already in low atmospheres, leading to dramaticallydecreased processing times and enhanced industrial applicability.

According to the invention it is possible to conduct the coating in amanner wherein the distance between the target material and said uniformsurface area to be coated is under 25 cm, preferably under 15 cm andmost preferably under 10 cm. This accomplishes the development ofcoating chambers with drastically diminished volumes, making the overallprice of coating production lines lower and decreasing further the timerequired for vacuum pumping.

In a preferred embodiment of the invention the ablated surface of saidtarget material can be repeatedly ablated in order to producedefect-free coating. In case of most of the present coatingtechnologies, the target material wears unevenly in a manner that theaffected area cannot be reused for ablation and must thus be eitherdiscarded or sent for regeneration after certain use. The problem hasbeen tackled by developing different techniques for feeding constantlynew, non-ablated target surface for coating purposes by for examplemoving the target material in x/y-axis or by rotating a cylinder-formedtarget material. The present invention accomplishes simultaneouslyexcellent coating properties and production rates as well as use oftarget material in a way wherein the good quality plasma retains itsquality throughout the use of substantially whole piece of targetmaterial. Preferably, more than 50% of the single target material weightis consumed to production of good quality plasma according to theinvention. With good quality plasma is hear meant plasma for producingdefect-free coatings and thin-films, the high quality of plasma plumebeing maintained at high pulse frequencies and deposition rates. Some ofsuch properties are described here below.

According to one embodiment of the invention, the average surfaceroughness of produced coating on said uniform surface area is less than100 nm as scanned from an area of 1 μm² with Atomic Force Microscope(AFM). More preferably, the average surface roughness is less than 30nm. With average surface roughness is here meant the average deviationfrom the centre line average curve fitted by a proper procedure, such asthose available in AFM or profilemeter. The surface roughness affectsamongst the other the wear- and scratch-free properties, tribologicalproperties as well as the transparency of coating on metal productscoated according to the invention.

In a still preferable embodiment of the invention, the opticaltransmission of produced coating on said uniform surface area is no lessthan 88%, preferably no less than 90% and most preferably no less than92%. It can even be higher than 98%. In some cases it can be beneficialto have limited optical transparency. Such examples includesafety-screens, non-transparent windows, sun-glasses, protective screensfor either sun-light or UV-light or other radiation.

In another embodiment of the invention, produced coating on said uniformsurface area contains less than one pinhole per 1 mm², preferably lessthan one pinhole per 1 cm² and most preferably no pinholes at saiduniform surface area. Pinhole is a hole going through or substantiallythrough the coating. Pinholes provide a platform for erosion of theoriginally coated material for example by chemical or environmentalfactors. Single pinhole in for instance coating of chemical reactor ortubing, medical implant, space ship, different parts of differentvehicles and their plastic mechanical parts or further, in metallicconstruction protected by said plastic coating, or interior structureleads easily to dramatically lowered life-time of said product.

Thus, in another preferred embodiment said uniform surface area iscoated in a manner wherein the first 50% of said coating on said uniformsurface area does not contain any particles having a diameter exceeding1000 nm, preferably 100 nm and most preferably 30 nm. If the earlystages of the coating manufacturing process produce micrometer sizeparticles, such particles can cause open corrosion pathways in the nextlayers of produced coating. Moreover, due to irregular shape ofparticles, it is extremely difficult to seal the surface underneath suchparticles. Additionally, such particles increase surface roughnesssubstantially. The present method allows even here increased lifetimeand lowered maintenance cost of different plastic products.

The plastic product itself can comprise virtually whichever plastic,plastic compound such as composite materials or mixtures of these.Preferable plastic grades include such as polyethylene (PE), polystyrene(PS), polyvinylchloride (PVC), polycarbonate (PC),polytetrafluoroethylene (Teflon), polyimide (PI, Kapton), Mylar, PEEK,cellulose-derived plastics, polyamides etc. In one embodiment of theinvention, the polymer material is also subjected to lithography. Insuch applications it is preferable to use polymers withstandingtemperatures up to 100° C. Additionally, said plastic product cancomprise virtually whichever 3D-structure.

Due to huge volumes of plastic products, one especially preferredembodiment of the invention is to coat plastic product already in itssheet form, and here, preferably in a coating station integrated intoplastic sheet (or 3D-product) production line. In such an approach, theuncoated plastic product is not contaminated with anysubstances/dirt/reaction and unnecessary surface treatment steps toremove such possible contaminants prior coating are avoided. The sameapplies for both large sheets such as polycarbonate sheets but also forsmaller plastic products such as lenses of mobile devices.

According to one embodiment of the invention, said uniform surface areaof plastic product is coated with metal, metal oxide, metal nitride,metal carbide or mixtures of these. Non-limiting examples of metalsinclude aluminum, molybdenum, titan, zirconium, copper, yttrium,magnesium, lead, zinc, ruthenium, chromium, rhodium, silver, gold,cobalt, tin, nickel, tantalum, gallium, manganese, vanadium, platinumand virtually whichever metal.

When producing coatings according to invention which comprise bothexcellent optical, wear, and scratch-free properties, especiallyadvantageous metal oxides are for example aluminum oxide and itsdifferent composites such as aluminum titan oxide (ATO). Due to itsresistivity, high-optical transparencies possessing high-quality indiumtin oxide (ITO) is especially preferred in applications wherein thecoating can be employed to warm-up the coated surface. It can also beemployed in solar-control. Ytrium stabilized zirconium oxide is anotherexample of different oxides possessing both excellent optical,wear-resistant and scratch-free properties. Some metals can be appliedin solar cell applications. Here, the actual cells are many times grownon plastic and the demand for reproducible, low-cost and high-qualitycoatings producing methods is increasing steadily. Here, the opticalproperties of metal-derived thin-films are somewhat different from thoseof bulk metals. In ultrathin films (<100 Å thick) variations make theconcept of optical constants problematic, the quality and surfaceroughness of the coating (thin film) being thus critical technicalfeatures. Such coatings can easily be produced with the method ofpresent invention.

As most of the pure metals, all the metals usually employed as mirrors(Al, Ag, Au, Cu, Rh and Pt) regardless their use are easily subjected tooxidation (Al), sulfide tarnishing (Ag) and mechanical scratching.Mirrors must therefore be coated with hard transparent protectivelayers. Thus, films of SiO, SiO₂ and Al₂O₃ are commonly used to protectevaporated Al mirrors, but usually at the cost of increasing absorbance.The problem can be tackled with present invention by producing hardcoatings comprising better optical transparencies and heatconductivities. At present, various substrate film glue (e.g. Al₂O₃,SiO) are used to improve adhesion, but Ag film use in mirrors remainsrestricted. The adhesion of appropriate films can be enhanced byproducing both now employed films and other enhanced carbon-based filmssuch as diamond and carbon nitride with the method of present invention.

Dielectric materials employed in present optical coating applicationsinclude fluorides (e.g. MgF₂, CeF₃), oxides (e.g. Al₂O₃, TiO₂, SiO₂),sulfides (e.g. ZnS, CdS) and assorted compounds such as ZnSe and ZnTe.An essential common feature of dielectric optical materials in theirvery low absorption (α<10³/cm) in some relevant portion of the spectrum;in this region they are essentially transparent (e.g. fluorides andoxides in the visible and infrared, chalcogenides in the infrared).

Dielectric coatings can now be advantageously produced on plastics withthe method of present invention.

Somewhere between dielectrics and metals is a class of materials calledtransparent conductors. According to electromagnetic theory, highconductivity and optical transparency are mutually exclusive propertiessince photons are strongly absorbed by the high density of chargecarriers. Although there are materials that separately are far moreconductive or transparent, the transparent conductors dealt with hereexhibit a useful compromise of both desirable properties. Broadlyspeaking, transparent conducting films consist either of very thinmetals or semi-conducting oxides and/ and most presently even nitridessuch as indiumgalliumnitride in solar cell applications. The firstwidespread use of such films was to transparent electrical heaters inaircraft windshield de-icing during World War II. Today, they aresomewhat used for automobile and airplane window defrosters, liquidcrystal and gas-discharge displays, front electrodes for solar cells,antistatic coatings, heating stages for optical microscopes,IR-reflectors, photoconductors in television camera vidicons, and Pockelcells for laser Q-switches.

Metals that have conventionally been employed be as transparentconductors include Au, Pt, Rh, Ag, Cu, Fe and Ni. Simultaneousoptimization of conductivity and transparency presents a considerablechallenge in film deposition. At one extreme are discontinuous islandsof considerable transparency but high resistivity; at the other arefilms that coalesce early and are continuous, possessing highconductivity but low transparency. For these reasons, thesemi-conducting oxides such as SnO₂, In₂O₃, CdO, and, more commonly,their alloys (e.g. ITO), doped In₂O₃ (with Sn, Sb) and doped SnO₂ (withF, Cl, etc.) are used.

The prior art deposition systems include both chemical and physicalmethods. Hydrolysis of chlorides and pyrolysis of metalorganic compoundsare examples of the former, reactive evaporation and sputtering inoxygen environment being examples of the latter—none of the systemsbeing beneficial for plastics. Optimum film properties requiremaintenance of tight stoichiometry. The prior art techniques employcommonly glass substrates and in such techniques the glass body iscommonly heated up close to the softening temperature. In that system,care must be taken to prevent stresses and warpage of the final product.Such system can not be employed at all to heat sensitive plastic bodies.Thus, the present method of invention also solves the problemsassociated with softening temperature with glass products and yieldssaid films in high quality and economically feasible manner.

For the most part, n in fluoride and oxide films has a value less than 2at the reference wavelength of 0.55 μm. For many applications, however,it is important to have films with higher refractive index in thevisible range. To meet these needs, materials like ZnS and XnSe aretypically employed. High transmittance is an essential requirement inoptical films, and as an arbitrary criterion only materials with anabsorption constant less than α=10³/cm are entered in the followinglist: NaF (c), LiF (c), CaF₂ (c), Na₃AlF₆ (c), AlF₃ (a), MgF₂ (c), ThF₄(a), LaF₃ (c), CeF₃ (c), SiO₂ (a), Al₂O₃ (a), MgO (c), Y₂O₃ (a), La₂O₃(a), CeO₂ (c), ZrO₂ (a), SiO (a), ZnO (c), TiO₂, ZnS (c), CdS (c), ZnSe(c), PbTe, Si (a), Ge (a); (c)=crystalline; (a)=amorphous.

In practice, however, only films with significantly lower absorption canbe tolerated. For example, in laser AR coatings losses must be kept toless than 0.01%, corresponding to k≈4×10−5 or α=10/cm at λ=5500 Å.

The present method of invention solves the problems associateddifficulties to yield films with higher refractive index in the visiblerange and accomplishes the production of said films in high quality andeconomically feasible manner. Moreover, it is now possible to produceabove listed materials and compounds in crystalline form, enhancingfurther the film properties.

If certain metal oxides such as titan oxide and zinc oxide are appliedon surface thicknesses providing UV-activity of produced coating, thecoating can possess self-cleaning properties. Such properties are highlydesired in order to accomplish the use and decrease the maintenance costof several metal products in both interior and exterior use.

The metal oxide coatings can be produced by either ablating metal ormetals in active oxygen atmosphere or by ablating oxide-materials. Evenin latter possibility, it is possible to enhance the coating qualityand/or production rate by conducting the ablation in reactive oxygen.When producing nitrides it is according to the invention possible to usenitrogen atmosphere or liquid ammonia in order to enhance the coatingquality. A representative example of invention is production of carbonnitride (C₃N₄ films).

If certain metal oxides such as titan oxide and zinc oxide are appliedon surface thicknesses providing UV-activity of produced coating, thecoating can possess self-cleaning properties. Such properties are highlydesired in order to accomplish the use and decrease the maintenance costof several metal products in both interior and exterior use.

The metal oxide coatings can be produced by either ablating metal ormetals in active oxygen atmosphere or by ablating oxide-materials. Evenin latter possibility, it is possible to enhance the coating qualityand/or production rate by conducting the ablation in reactive oxygen.When producing nitrides it is according to the invention possible to usenitrogen atmosphere or liquid ammonia in order to enhance the coatingquality. A representative example of invention is production of carbonnitride films (C₃N₄).

According another embodiment of the invention, said uniform surface areaof plastic product is coated with carbon material comprising over 90atomic-% of carbon, with more than 70% of sp³-bonding. Such materialsinclude for example amorphous diamond, nano-crystalline diamond or evenpseudo-monocrystalline diamond. Various diamond coatings give theplastic product excellent tribological, wear- and scratch-freeproperties but increase also the heat-conductivity and -resistance.

Diamond-coatings on plastics can be used with special preference inprotective eye-ware, in electronic device displays, in protecting glassequipment applied in hazardous conditions, and if of high quality, i.e.crystalline form, is semiconductor applications, in solar cells, indiode pumps for instance for laser applications etc.

In a still another embodiment of the invention, said uniform surfacearea of plastic product is coated with material comprising carbon,nitrogen and/or boron in different ratios. Such materials include boroncarbon nitride, carbon nitride (both C₂N₂ and C₃N₄), boron nitride,boron carbide or phases of different hybridizations of B—N, B—C and C—Nphases. Said materials are diamond-like materials having low densities,are extremely wear-resistant, and are generally chemically inert. Forexample carbon nitrides can be employed to protect metal productsagainst corrosive conditions, as coatings for medical devices andimplants, battery electrodes, humidity and gas sensors, semiconductorapplications, protecting computer hard disks, in solar cells, tools,etc.

According to one embodiment of the invention certain uniform surfacearea of plastic product is coated with organic polymer material. Suchmaterials include but are not limited to chitosan and its derivatives,polysiloxanes, and different organic polymers.

By coating metal product with chitosan there are promising perspectivesto produce a new class of plastic products for marine and other waterenvironments as well as new plastic products for both interior andexterior use.

Here, polysiloxanes are especially advantageous for manufacturingproducts with relatively high wear-resistance and scratch-freeproperties with simultaneously excellent optical transparencies.

According to still another embodiment of invention said uniform surfacearea is coated with inorganic material. Such materials include but arenot limited to for instance stone and ceramic derived materials.

In an especially preferred embodiment of the invention, differentplastic sheets and 3D-metal structures were coated by ablating a targetmaterial comprising pink agate resulting in colored but opaque coatingresult.

According to one embodiment of invention, said uniform surface of theplastic product is coated with only one single coating. According toanother embodiment of the invention, said uniform surface of the plasticproduct is coated with multilayered coating. Several coatings can beproduced in for different reasons. One reason might be to enhance theadhesion of certain coatings to plastic product surface by manufacturinga first set of coating having better adhesion to plastic surface andpossessing such properties that the following coating layer has betteradhesion to said layer than to plastic surface itself. Additionally, themultilayered coating can possess several functions not achievablewithout said structure. The present invention accomplishes theproduction of several coatings in one single coating chamber or in theadjacent chambers.

The present invention further accomplishes the production of compositecoatings to plastic product surface by ablating simultaneously onecomposite material target or two or more target materials comprising oneor more substances.

According to invention the thickness of said coating on uniform surfaceof plastic product is between 20 nm and 20 μm, preferably between 100 nmand 5 μm. The coating thicknesses must not be limited to those, becausethe present invention accomplishes the preparation of molecular scalecoatings on the other hand, very thick coatings such as 100 μm and over,on the other hand.

The present invention further accomplishes the preparation of3D-structures employing the plastic component as a scaffold for growingsaid 3D-structure.

According to the invention there is also provided a plastic productcomprising a certain surface being coated by laser ablation wherein thecoated uniform surface area comprises at least 0.2 dm² and that thecoating has been carried by employing ultra short pulsed laserdeposition wherein pulsed laser beam is scanned with a rotating opticalscanner comprising at least one mirror for reflecting said laser beam.The benefits received with these products are described in more detailin the previous description of the method.

In a more preferred embodiment of the invention said uniform surfacearea comprises at least 0.5 dm². In a still more preferable embodimentof the invention said uniform surface area comprises at least 1.0 dm².The invention accomplishes easily also the products comprising uniformcoated surface areas larger than 0.5 m², such as 1 m² and over.

According to one embodiment of the invention the average surfaceroughness of produced coating on said uniform surface area is less than100 nm as scanned from an area of 1 μm² with Atomic Force Microscope(AFM). Preferably, the uniform surface roughness is less than 50 nm andmost preferably it is under 25 nm. According to another embodiment ofthe invention the optical transmission of produced coating on saiduniform surface area is no less than 88%, preferably no less than 90%and most preferably no less than 92%. In some cases the opticaltransmission can exceed 98%.

According to still another embodiment of the invention said producedcoating on said uniform surface area contains less than one pinhole per1 mm², preferably less than one pinhole per 1 cm² and most preferably nopinholes at said uniform surface area.

According to still another embodiment of the invention said uniformsurface area is coated in a manner wherein the first 50% of said coatingon said uniform surface area does not contain any particles having adiameter exceeding 1000 nm, preferably 100 nm and most preferably 30 nm.

The plastic product according to the invention can comprise virtuallywhichever plastic, plastic compound such as composite materials ormixtures of these. As mentioned earlier, the definition of plasticproduct in this connection must be understand in a manner, wherein theproduct comprises a certain plastic surface, which has been coatedaccording to now invented method. The plastic content of the productscaffold (uncoated product) can thus vary everywhere between 0.1 to100%.

According to one embodiment of the invention said uniform surface areaof plastic product is coated with metal, metal oxide, metal nitride,metal carbide or mixtures of these. The possible metals were describedearlier in description of now invented coating method.

According to another embodiment of the invention said uniform surfacearea of plastic product is coated with carbon material comprising over90 atomic-% of carbon, with more than 70% of sp³-bonding. The possiblecarbon materials were described earlier in description of now inventedcoating method.

According to still another embodiment of the invention said uniformsurface area of plastic product is coated with material comprisingcarbon, nitrogen and/or boron in different ratios. Such materials weredescribed earlier in description of now invented coating method.

According to still another embodiment of the invention said uniformsurface area of plastic product is coated with organic polymer material.Such materials were described earlier in more detail in description ofnow invented coating method.

According one embodiment of the invention said uniform surface area iscoated with inorganic material. Such materials were described earlier inmore detail in description of now invented coating method.

According to another preferred embodiment of the invention said uniformsurface of plastic product is coated with multilayered coating.According to another preferred embodiment of the invention said uniformsurface of plastic product is coated with single coating layer.

According to one preferred embodiment of the invention the thickness ofsaid coating on uniform surface of plastic product is between 20 nm and20 μm, preferably between 100 nm and 5 μm. The invention accomplishesalso coated plastic products comprising one or several atomic layercoatings and thick coatings such as exceeding 100 μm, for example 1 nm.The present invention further accomplishes the 3D-structures prepared byemploying the plastic component as a scaffold for growing said3D-structure.

EXAMPLES Example to Demonstrate Known Art Problems—Laser Technology

FIG. 2 represents the ITO-coating on polycarbonate sheet (˜100 mm×30 mm)produced by employing a prior art optical scanner, namely vibratingmirror (galvo-scanner), in different ITO thin-film thicknesses (30 nm,60 nm and 90 nm). Although the ITO-coating is not deposited on metalsubstrate, the picture clearly demonstrates some of the problemsassociated with employing vibrating mirror as an optical scannerespecially in ultra short pulsed laser deposition (USPLD) but also inlaser assisted coatings in general. As a vibrating mirror changes itsdirection of angular movement at its end positions, and due to momentinertia, the angular velocity of the mirror is not constant near to itsend positions. Due to vibrating movement, the mirror continuously brakesup and stops before speeding up again, causing thus irregular treatmentof the target material at the edges of the scanned area. As it can beseen from FIG. 2, this in turn results in low quality plasma comprisingparticles especially in the edges of the scanned area and finally, inlow quality and seemingly uneven coating result.

The coating parameters have been selected in order to demonstrate theuneven distribution of ablated material due to the nature of employedscanner. If selecting the parameters appropriately, the film quality canbe enhanced, problems becoming invisible but not excluded.

Example to Demonstrate Known Art Problems—Laser Technology

Conventionally galvanometric scanners are used to scan a laser beam witha typical maximum speed of about 2-3 m/s, in practice about 1 m/s. Thismeans that even 40-60 pulses are overlapping with a repetition rate of 2MHz (FIG. 3).

Example to Demonstrate Known Art Problems—Laser Technology

Plasma related quality problems are demonstrated in FIGS. 30 a and 30 b,which indicate plasma generation according to known techniques. A laserpulse □ 1114 hits a target surface 1111. As the pulse is a long pulse,the depth h and the beam diameter d are of the same magnitude, as theheat of the pulse 1114 also heat the surface at the hit spot area, butalso beneath the surface 1111 in deeper than the depth h. The structureexperiences thermal shock and tensions are building, which whilebreaking, produce fragments illustrated F. As the plasma may be in theexample quite poor in quality, there appears to be also molecules andclusters of them indicate by the small dots 1115, as in the relation tothe reference by the numeral 1115 for the nuclei or clusters of similarstructures, as formed from the gases 1116 demonstrated in the FIG. 30 b.The letter “o”s demonstrate particles that can form and grow from thegases and/or via agglomeration. The released fragments may also grow bycondensation and/or agglomeration, which is indicated by the curvedarrows from the dots to Fs and from the os to the Fs. Curved arrowsindicate also phase transitions from plasma 1113 to gas 1116 and furtherto particles 1115 and increased particles 1117 in size. As the ablationplume in FIG. 30 b can comprise fragments F as well as particles builtof the vapours and gases, because of the bad plasma production, theplasma is not continuous as plasma region, and thus variation of thequality may be met within a single pulse plume. Because of defects incomposition and/or structure beneath the deepness h as well as theresulting variations of the deepness (FIG. 30 a), the target surface1111 in FIG. 30 b is not any more available for a further ablations, andthe target is wasted, although there were some material available.

Example of Invention—1

FIG. 28 a demonstrates a target material ablated with pico-second-rangepulsed laser employing rotating scanner with speed accomplishing theablation of target material with slight overlapping of adjacent pulses,avoiding the problems associated with prior art galvano-scanners. FIG.28 b shows enlarged picture of one part of the ablated material, clearlydemonstrating the smooth and controlled ablation of material on both x-and y-axis and thus, generation of high quality, particle-free plasmaand further, high quality thin-films and coatings. FIG. 28 cdemonstrates one example of possible x- and y-dimensions of one singleablation spot achieved by one or few pulses. Here, it can be clearlyseen, that the invention accomplishes the ablation of material in amanner wherein the width of the ablated spot is always much bigger thanthe depth of the ablated spot area. Theoretically, the possibleparticles (if they would be generated) could now have a maximum size ofthe spot depth. The rotating scanner now accomplishes the production ofgood quality, particle free plasma with great production rate, withsimultaneously large scanning width, especially beneficial forsubstrates comprising large surface areas to be coated. Furthermore, theFIGS. 28 a, 28 b and 28 c clearly demonstrate that opposite to presenttechniques, the already ablated target material area can be ablated fornew generation of high class plasma˜reducing thus radically the overallcoating/thin-film producing cost.

Example of Invention—2

FIG. 29 a demonstrates an example wherein coating is carried out byemploying a pico-second USPLD-laser and scanning the laser pulses withturbine scanner. Here, the scanning speed is 30 m/s, the laserspot-width being 30 μm. In this example, there is an ⅓ overlappingbetween the adjacent pulses.

Examples of Invention—Coated Products

The following samples were grown on various plastic substrates byemploying ultra short pulsed laser deposition (USPLD) with apicosecond-range laser (X-lase, 20-80 W) at 1064 nm. Substratetemperature was varied in the range of 50-120° C. and target temperaturein the range of room temperature to 700° C. The utilized spot sizevaried between 20 μm to 70 μm, being in most of the coating runs 40 μm.Both oxide, sintered graphite, sintered graphitic C₃N₄H_(x) (CarbodeonLtd Oy) and various metal targets were employed. When employing oxygenatmosphere, the oxygen pressure varied n the range of 10⁻⁴ to 10⁻¹ mbar.When employing nitrogen atmosphere, the nitrogen pressure varied n therange of 10⁻⁴ to 10⁻¹ mbar. The plastic samples were preferablyoven-dried prior coating procedure. The employed scanner was a rotatingmirror scanner accomplishing tunable velocity of the beam at the surfaceof the target between 1 m/s to 350 m/s. The employed repetition ratesvaried between 1 to 30 MHz, clearly demonstrating the importance of boththe scanner and high repetition rates when producing high qualitycoatings in industrial manner. Deposited films were characterized byconfocal microscope, FTIR and Raman spectroscopy, AFM, opticaltransmission measurements, ESEM and in some cases, electricalmeasurements (University of Kuopio, Finland; ORC, Tampere, Finland andCorelase Oy, Tampere Finland). The employed spot sizes varied between 20to 80 μm. The wear tests were carried out by employing pin ondisk-method (University of Kuopio, Finland), the tests being carried outat room temperature 22 C and 50% (AD-coatings) or 25% (others) relativehumidity (without lubrication) with loads in the range 10-125 g using ahardened steel ball (AISI 420), 6 mm in diameter, as a pin. ForAD-coatings the rotation speed was 300-600 rpm and for lenses 1 rpm. Allthe coatings possessed excellent wear properties as well as adhesions.No macroparticles due to deposition were observed on imaged areas. Insome applications the existence of pinholes would not be a criticalissue.

Example 1

A sheet of polycarbonate comprising 100 mm×200 mm was coated by ablatingsintered carbon with pulse repetition rate of 4 MHz, pulse energy 2.5μJ, pulse length 20 ps and the distance between the target material andsurface to be coated was 8 mm. The vacuum level was 10⁻⁵ atmospheresduring the coating process. The process resulted in a uniformpale-brown, transparent coating. The coating thickness was 150 nm andthe average surface roughness was determined to be 20 nm as scanned froman area of 1 μm² with Atomic Force Microscope (AFM). No pinholes ordetectable particles were found on any measured area.

Example 2

Several lacquer coated plastic lenses (Finnsusp, Finland) was coated byablating aluminum titan oxide (ATO) with pulse repetition rate of 4 MHz,pulse energy 5 μJ, pulse length 20 ps and the distance between thetarget material and surface to be coated was 25 mm. The vacuum level was10⁻⁵ atmospheres during the coating process. The process resulted in auniform, transparent coating. The coating thicknesses varied between 100to 600 nm and the average surface roughness was determined to be under10 nm as scanned from an area of 1 μm² with Atomic Force Microscope(AFM). No pinholes or detectable particles were found on any measuredarea.

Here, the wear resistance was tested by using a pin-on-disk testing withvarying loads 10-100 g and test runs lasting 250-1000 rounds. Comparisonof coated lens to commercial lenses was done by comparing the preparedcoating (FIG. 23, right side) to two commercial French lenses(Commercial A and B) and MaxiAR coated lens by Finnsusp Ltd (CommercialC, FIG. 23, lens on left side). Lenses A and B were damaged in test runseasily even with low loads and short runs. On the contrary, the lens C(Finnsusp comparative sample) was significantly more wear resistant andwithstands high loads without significant damage to the surface althoughthe uttermost this surface layers were slightly worn. The transparencywas not altered unless the coating damaged fully.

The wear resistance of ATO-coated lens was best, the comparison of wearresistance between the samples being presented as maximum load withoutdamages for 1000 rounds in table 1 below:

TABLE 1 Test Max Load Without lens Failure @1000 rounds Comm. A <15 gComm. B <15 g Comm. C 25-50-75 g Picodeon Ltd ≧100 g

Example 3

Several sheets of polycarbonate comprising 300 mm×200 mm One was coatedby ablating yttrium stabilized zirconium oxide with repetition rate of 2Mhz, pulse energy 5 μJ, pulse length 20 ps and the distance between thetarget material and surface to be coated was 45 mm. The vacuum level was10⁻⁵ atmospheres during the coating process. The process resulted in auniform, transparent coating. The coating thickness was measured from100 nm even to 1 μm and the average surface roughness was determined tobe below 3 nm as scanned from an area of 1 μm² with Atomic ForceMicroscope (AFM). No pinholes were found on any measured area.

The oxide coated final product possessed remarkably better wearresistance and scratch-free properties as compared to commercialpolycarbonate sheet. The surface profiles of the wear track for acommercial PC-plate after wear testing are presented in FIG. 26(commercial product) and FIG. 27, the optical micrographs of the weartracks being represented in FIGS. 24 and 25, respectively. The figuresclearly demonstrate the difference in favor to yttrium stabilizedzirconium oxide-coated pc-plate. Please, note also the differentvertical scales of FIGS. 26 and 27. The adhesion of the coatingstructure was good.

Example 4

A sheet of polycarbonate comprising 300 mm×250 mm was coated by ablatingtitan oxide in oxygen atmosphere with pulse repetition rate of 2 MHz,pulse energy 4 μJ, pulse length 10 ps and the distance between thetarget material and surface to be coated was 45 mm. The vacuum level was10⁻² atmospheres during the coating process. The process resulted intransparent coating possessing coating thickness of 20 nm. The averagesurface roughness was determined to be 2 nm as scanned from an area of 1μm² with Atomic Force Microscope (AFM). No pinholes were found on anymeasured area of titan oxide-coating. The coated object was subjected toorganic dirt after which it was subjected to light and certain humidity.The coating possessed self-cleaning properties.

Example 5

A sheet of polycarbonate comprising 300 mm×250 mm was coated by ablatingtitanium with pulse repetition rate of 12 MHz, pulse energy 5 μJ, pulselength 20 ps and the distance between the target material and surface tobe coated was 60 mm. The vacuum level was 10⁻⁴ atmospheres during thecoating process. The process resulted in metallic titan coatingpossessing coating thickness of 50 nm. The average surface roughness wasdetermined to be 0.14 nm as scanned from an area of 1 μm² with AtomicForce Microscope (AFM). No pinholes were found on any measured area oftitanium-coating.

Example 6

A sheet of polycarbonate comprising 300 mm×250 mm was coated by ablatingpink agate (crushed and sintered) with pulse repetition rate of 15 MHzand the distance between the target material to be coated was 3 cm. Thevacuum level was 10⁻⁵ atmospheres during the coating process. Theprocesses resulted in pink agate coloured, opaque coatings comprisingthickness of 100 nm. The average surface roughness was determined to beunder 3 nm as scanned from an area of 1 μm² with Atomic Force Microscope(AFM). No pinholes were found on any measured area of agate coating.

Example 7

A sheet of polycarbonate comprising 300 mm×250 mm was coated by ablatingcold-pressed chitosan with pulse repetition rate of 2.5 MHz, pulseenergy 5 μJ, pulse length 19 ps and the distance between the targetmaterial and surface to be coated was 25 mm. The vacuum level was 10⁻⁷atmospheres during the coating process. The process resulted inpartially opaque coating possessing coating thickness of 280 nm. Theaverage surface roughness was determined to be 10 nm as scanned from anarea of 1 μm² with Atomic Force Microscope (AFM). No pinholes were foundon any measured area of chitosan-polymer coating.

Example 8

A sheet of polycarbonate comprising 10 mm×25 mm was coated by ablatinghot-pressed C₃N₄H_(x) with pulse repetition rate of 1 MHz, pulse energy5 μJ, pulse length 20 ps and the distance between the target materialand surface to be coated was 65 mm. Nitrogen pressure varied in therange of 10⁻⁴ to 10⁻¹ mbar. The coating thickness was measured to 100nm. The average surface roughness was determined to be under 3 nm asscanned from an area of 1 μm² with Atomic Force Microscope (AFM). Nopinholes were found on any measured area of carbon nitride coating.

Example 9

A sheet of polycarbonate comprising 100 mm×250 mm was coated by ablatingITO in oxide form (90 wt. % In₂O₃; 10 wt. % SnO₂) with pulse repetitionrate of 22 MHz, pulse energy 5 μJ, pulse length 20 ps and the distancebetween the target material and surface to be coated was 12 cm. Oxygenpressure varied in the range of 10⁻⁴ to 10⁻¹ mbar. The process resultedin a uniform, transparent coating. The coating thickness was measured to220 nm and the average surface roughness was determined to be under 3 nmas scanned from an area of 1 μm² with Atomic Force Microscope (AFM). Nopinholes were found on any measured area of ITO coating. Electricalresistivity of the sample was measured to 2.2×10⁻³ Ωcm.

Example 10

A sheet of acryl plastics comprising 100 mm×100 mm was coated byablating ITO from a metal target (90 wt. % In; 10 wt. % Sn) with pulserepetition rate of 16 MHz, pulse energy 5 μJ, pulse length 20 ps and thedistance between the target material and surface to be coated was 6 cm.Oxygen pressure varied in the range of 10⁻⁴ to 10⁻¹ mbar. The processresulted in a uniform, transparent coating. The coating thickness was 40nm and the average surface roughness was determined to be under 2 nm asscanned from an area of 1 μm² with Atomic Force Microscope (AFM). Nopinholes were found on any measured area of the ITO coating.

Example 11

A sheet of acryl plastics comprising 100 mm×100 mm was coated byablating aluminum oxide with pulse repetition rate of 4 MHz, pulseenergy 5 μJ, pulse length 20 ps and the distance between the targetmaterial and surface to be coated was 2 cm and the vacuum level was 10⁻³atmospheres during the coating process. The process resulted in auniform, transparent coating. The coating thickness was 800 nm and theaverage surface roughness was determined to be under 3 nm as scannedfrom an area of 1 μm² with Atomic Force Microscope (AFM). No pinholeswere found on any measured area of the aluminumoxide coating.

Example 12

The ITO-coated sample of example 10 was coated by ablating aluminumoxidewith same conditions as in previous sample 11. The process resulted in auniform, transparent coating. The aluminumoxide coating thickness wasagain 800 nm and the average surface roughness was determined to beunder 3 nm as scanned from an area of 1 μm² with Atomic Force Microscope(AFM). No pinholes were found on any measured area of the aluminum oxidecoating.

Example 17

A polycarbonate sheet with surface area comprising 300 mm×300 mm wascoated with aluminum oxide (Al₂O₃) by ablating metallic aluminum fed asfoil in active oxygen atmosphere the oxygen pressure varying in therange of 10⁻⁴ to 10⁻¹ mbar. with repetition rate of 12 MHz, pulse energy4.5 μJ, pulse length 20 ps and the distance between the target materialand surface to be coated adjusted to 25 mm. The vacuum level was 10⁻⁵atmospheres before the actual coating process. The process resulted inan uniform aluminium oxide-coating. The coating thickness of aluminumoxide coating was 500 nm and the average surface roughness wasdetermined to be below 4 nm as scanned from an area of 1 μm² with AtomicForce Microscope (AFM). No pinholes were found on any measured area.

Example 18

Sheets of mylar and polyethylene comprising 100 mm×250 mm were coated byablating ITO in oxide form (90 wt. % In₂O₃; 10 wt. % SnO₂) with pulserepetition rate of 15 MHz, pulse energy 5 μJ, pulse length 20 ps and thedistance between the target material and surface to be coated was 50 mm.Oxygen pressure varied in the range of 10⁻⁴ to 10⁻¹ mbar. The processresulted in uniform, transparent coatings. The coating thicknesses weremeasured to 150 nm and 180 nm and the average surface roughness wasdetermined to be under 3 nm as scanned from an area of 1 μm² with AtomicForce Microscope (AFM) in both of the samples. No pinholes were found onany measured area of ITO coatings.

Electrical resistivity of both of the samples was measured to 2.4×10⁻³Ωcm.

Example 19

Sheets of polyvinylchloride, polyimide, polystyrene and acryl comprisingsurfaces of 50 mm×450 mm were coated by ablating yttrium aluminumoxide(ATO) with pulse repetition rate of 4 MHz, pulse energy 5 μJ, pulselength 20 ps, the distance between the target material and surface to becoated being kept at 5 cm. The vacuum level was 10⁻² atmospheres duringthe coating processes. The process resulted in a uniform, transparentcoating. The coating thickness was 440 nm, 440 nm, 450 nm and 460 nmrespectively, and the average surface roughness were determined to beunder 3 nm as scanned from an area of 1 μm² with Atomic Force Microscope(AFM) in all of the samples. No pinholes were found on any measured areaof the ATO-coatings.

1-33. (canceled)
 34. A method for coating a certain surface of a plasticproduct by laser ablation, characterized in that the uniform surfacearea to be coated comprises at least 0.2 dm² and the coating is carriedby employing ultra short pulsed laser deposition wherein pulsed laserbeam is scanned with a rotating optical scanner comprising at least onemirror for reflecting said laser beam.
 35. A method according to claim34, characterized in that said uniform surface area comprises at least0.5 dm², preferably at least 1.0 dm².
 36. A method according to claim34, characterized in that the employed pulse frequency of said laserdeposition is at least 1 MHz.
 37. A method according to claim 34,characterized in that the average surface roughness of produced coatingon said uniform surface area is less than 100 nm as scanned from an areaof 1 μm² with Atomic Force Microscope (AFM).
 38. A method according toclaim 34, characterized in that said uniform surface area of plasticproduct is coated with material comprising at least one of followingmaterials or a mixture of these: metal, metal oxide, metal nitrideand/or metal carbide; or carbon, nitrogen and/or boron; or carbonmaterial comprising over 90 atomic-% of carbon, with more than 70% ofsp³-bonding; or organic polymer material; or inorganic material.
 39. Amethod according to claim 34, characterized in that said uniform surfaceof plastic product is coated with multilayered coating.
 40. A methodaccording to claim 34, characterized in that the thickness of saidcoating on uniform surface of plastic product is between 20 nm and 20μm, preferably between 100 nm and 5 μm.
 41. A plastic product comprisinga certain surface being coated by laser ablation, characterized in thatthe coated uniform surface area comprises at least 0.2 dm² and that thecoating has been carried by employing ultra short pulsed laserdeposition wherein pulsed laser beam is scanned with a rotating opticalscanner comprising at least one mirror for reflecting said laser beam.42. A plastic product according to claim 41, characterized in that saiduniform surface area comprises at least 0.5 dm², preferably at least 1.0dm².
 43. A plastic product according to claim 41, characterized in thatthe average surface roughness of produced coating on said uniformsurface area is less than 100 nm as scanned from an area of 1 μm² withAtomic Force Microscope (AFM).
 44. A plastic product according to claim41, characterized in that the optical transmission of produced coatingon said uniform surface area is no less than 88%, preferably no lessthan 90% and most preferably no less than 92%.
 45. A plastic productaccording to claim 41, characterized in that the said produced coatingon said uniform surface area contains less than one pinhole per 1 mm²,preferably less than one pinhole per 1 cm² and most preferably nopinholes at said uniform surface area.
 46. A plastic product accordingto claim 41, characterized in that said uniform surface area is coatedin a manner wherein the first 50% of said coating on said uniformsurface area does not contain any particles having a diameter exceeding1000 nm, preferably 100 nm and most preferably 30 nm.
 47. A plasticproduct according to claim 41, characterized in that said uniformsurface area of plastic product is coated with material comprising atleast one of following materials or a mixture of these: metal, metaloxide, metal nitride and/or metal carbide; or carbon, nitrogen and/orboron; or carbon material comprising over 90 atomic-% of carbon, withmore than 70% of sp³-bonding; or organic polymer material; or inorganicmaterial.
 48. A plastic product according to claim 41, characterized inthat said uniform surface of plastic product is coated with multilayeredcoating.
 49. A plastic product according to claim 41, characterized inthat the thickness of said coating on uniform surface of plastic productis between 20 nm and 20 μm, preferably between 100 nm and 5 μm.